Chromebook Tablet Mode Lag, Jank Getting A Fix

If you’ve used a Chrome OS tablet like the new Pixel Slate, Chromebook Tab 10, or the HP Chromebook x2, you may have come across an odd and annoying trait they all seem to share: jank and lag.

While not surprising on the under-powered Acer Chromebook Tab 10 and it’s Rockchip OP1 processor, this behavior is nearly infuriating on much more expensive devices with much more capable hardware like the HP x2 or Pixel Slate.

Looking around the internet, you can find many reviewers complaining about lag and jitters on the Pixel Slate while I was pretty happy with the overall performance.

Why is that? Well, for me, I use Chrome devices as laptops first. In laptop mode, I never really had any issues at all with performance. Opening apps and browser windows worked just like my Pixelbook. Multitasking was great. Honestly, the overall use felt just as smooth all around, even with the extra 250,000 extra pixels on the screen compared to the 2400×1600 resolution of the HP x2 and Pixelbook.

Given that I was testing the Core i5 model, I fully expected things to remain fast and snappy. The one and only place I encountered issue was in tablet mode, and that is precisely where you see other reviewers experiencing jank and stutters. Really, the tablet mode is just fine, but there is one very specific UI element that is not optimized and needs work: drag to overview mode.

On a Chrome OS tablet (and on convertibles in tablet mode), you can drag down from the top of the screen to enter overview mode. It is a natural and solid UI design and most users adapt to it quite quickly. The functionality is quite good and allows for some pretty great flow when in tablet mode. Take a look at the video we did on Chrome OS 70 to see it in action.

Now, note the date on that video. August 23, 2018. Yeah, this feature hasn’t been around very long. When we made that video just a few months back, these features were still in the Dev Channel. All this tablet UI is new and, frankly, still needs some work.

The odd part is, all other methods of overview mode work quite well. Three-finger swipes, the overview key, and the overview button in the bottom right corner in tablet mode all work very well. Sure, there are drops in frames here and there, but nothing like the mess of lagginess we see when users pull down from the top of the screen in tablet mode. Even on the Pixel-dense Slate, using the bottom corner multitask button keeps things mostly smooth regardless of how many windows I have open.

Also interesting, convertibles like the Dell Inspiron 14, HP Chromebook x360, and Lenovo Yoga C630 all handle this particular task with ease. My guess is the 1920×1080 screens on those devices help make this way less of a difficult processing task. Regardless, that isn’t a workable excuse when people are dropping upwards of over a thousand dollars on devices like the Pixel Slate.

The fix is coming, though.

If all the other methods of entering overview mode are in pretty good shape, it stands to reason that they can fix the gesture-based one, right? From the looks of this bug report, a fix is being worked on as we speak and has been a work in progress since mid-November.

From the bug:

A lot of animation jank seems to be coming from the use of Mask Layers to create rounded corners. This combined with background blur adds a lot of additional steps in the paint/rendering pipeline.

The performance (fps increase) and memory improvement (tiles dont get discarded and we actually see the content) is quite significant on Nocturne Celeron when rounded corners are removed.

So, it seems that all the animations and graphic elements that are happening in overview mode are causing some pipeline issues when users enter overview mode. This all gives the clear impression that the Pixel Slate is slow, laggy, and poorly made. Sure, none of that is exactly true. If you don’t use that feature, you’d feel the Pixel Slate is quite fast and fantastic at handling almost any task.

But, for a tablet, that overview mode is a central part of the UI, and that is a problem. As I said many times in my review, the Pixel Slate is first and foremost a tablet. When you buy it, you buy a tablet and add accessories to make it more than that. As a tablet, the drag to overview gesture is central to navigating the device and, if it is poorly done (which it is, currently), gives off the impression that the device is slow and poorly optimized.

It is unfortunate, honestly. The more I use the Slate, the more I like it. However, the terrible lag with overview mode makes me not want to use the tablet mode very often, and that really removes the central usefulness of this device over something like the Pixelbook.

Here’s hoping that this bug gets taken care of soon. According to the bug tracker, the priority is nearly the highest (it is a 1) and there are developers working on it as we speak. It looks like they are aiming to address the coding issues by Chrome OS 73, so don’t expect this next week.

As we move into 2019, I fully expect tablets and detachables to be the most prevelant form factor for Chrome OS moving forward. As part of that effort, Google needs to make sure things that make using tablets fun – like gesture navigation – are smooth and effortless. Right now that just isn’t the case.

About Robby Payne

Tech junkie. Musician. Web Developer. Coffee Snob. Huge fan of the Google things. Founded Chrome Unboxed because so many of my passions collide in this space. I like that. I want to share that. I hope you enjoy it too.